As is known in the art, alcohol-fueled vehicles in North America require a means to prevent siphoning of the fuel out the filler tube pipes. The common method of meeting this requirement is to install a plastic screen in the filler pipe 1 or fuel tank spud. One such filler tube 1 is shown in FIGS. 1A, 2 and 2A. The plastic screen typically is comprised of slender ribs 2 arranged in the cross section of the pipe 1 in a plane orthogonal to the cross section of the pipe and having a spacing distance between the ribs 2 that is sufficient to prevent insertion of a siphon hose 3 (FIG. 1B). Typical rib spacing is 5 mm as required by statute. The ribs 2 are slender in the direction of fuel flow (FIG. 3) in order to minimize the restriction they impose on fuel flow yet prevent a siphon 3 from reaching down into the fuel tank, as shown in FIG. 1B. Nevertheless, the ribs consume some of the flow area, and the flow must pass between the ribs 2. This raises the local velocity of the fluid and increases restriction, and thus the pressure drop across the filler pipe, as shown in FIG. 3. Increased pressure drop can cause dispensed fluid to back up the pipe 1 and prematurely shut off the dispenser nozzle. Thus, it is desired to meet the anti-siphon requirement while introducing the minimum possible flow restriction. While it is possible to simply increase the diameter of the filler tube to reduce restriction, that action could lead to difficulty packaging the filler pipe, increased manufacturing cost, and problems forming a liquid seal in the filler pipe as required to avoid vapors escaping out the top of the pipe during refueling.